[Quantified EEG in the diagnosis of Alzheimer's type dementia]. / Apport de l'EEG quantifié au diagnostic de démence de type Alzheimer.

79 subjects (mean age 70.2 ans, 31 males, 48 females) selected as probable dementia of the Alzheimer type, at the early stage of the disease and 17 normal aged people (mean age: 72.2, 5 males, 12 females) were recorded with a 16 channel computerized-EEG (C-EEG) with topographical analysis of the observed changes and with classical visual analysis of the EEG. Quite simple C-EEG parameters as mean dominant frequency (MF) and alpha to theta ratio are able to discriminate patients from normal with a greater accuracy than visual analysis. The values of 8.6 for the MF and 1.3 for the alpha/theta ratio are proposed as cut off values between normal and DAT patients. The topographical analysis appear to be of no additional usefulness in the discrimination of the two groups.

[The French Society of EEG and Clinical Neurophysiology is 40 years old]. / La Société d'EEG et de Neurophysiologie clinique de Langue française a 40 ans.

The historical reminder of the foundation of the French EEG Society and the changes which have occurred during its operation show the worry of the Society for a better efficiency all along this last fourty years. A general survey of the scientific activities disclose the contribution of the society in the papers first published in the Revue Neurologique, and, after 1971, in the Revue d'EEG et de Neurophysiologie clinique de Langue française. The French participation in other clinical neurophysiological or scientific meetings in France and abroad is underlined by the important role it has played in the life of the International Federation for EEG Societies. Training of specialized doctors and technicians in the domain of the functional exploration of the nervous system has been a standing preoccupation of the Society, with the teaching of the so-called "Attestation d'EEG" in French universities and the training of technical personnel in specialized schools.

[Role of electroencephalography in the diagnosis of acute cerebral diseases]. / Place de l'électroencéphalogramme dans le diagnostic des affections cérébrales aiguës.

It appears from a study of 100 cases of acute cerebral disease that electroencephalography is valuable as part of the diagnosis strategy and not only to establish the correct final diagnosis. This examination therefore plays a non-negligible role in neurological practice. In a number of diseases it provides information that no other examination can provide, being a dynamic, functional method of brain tissue analysis.

[Value of quantitative EEG and EEG mapping in medicine]. / Intérêt de l'EEG quantitatif et de la cartographie EEG en médecine.

Quantitative EEG consists in digitising the EEG from one or several leads and then mathematically processing the signal usually by Fourier spectral analysis. A reduction of the digital information gives characteristic parameters (frequency, amplitude or power, asymmetry, etc.), which can themselves be averaged and submitted to different statistical analysis. Quantitative EEG is particularly suitable for clinical electropharmacology for the assessment of the profiles of psychotropic drugs, for pharmacokinetic correlations of dose-effect relationships and studies of drug bioavailability. The signals obtained from schizophrenic and depressed patients have well defined quantitative EEG characteristics: dissymmetry of the amplitude and hypovariability of the EEG signals. EEg mapping is performed by computer processing of 16 simultaneous EEG lead recordings. This new form of medical imaging is fast, relatively economical and non-invasive, and it is used in psychophysiology to study cognitive tasks and the states of vigilance and sleep. It is also used to study the EEG topography of cerebrovascular accidents, brain tumours, cranial trauma, cerebral degeneration and dementia, and the EEGs of psychiatric patients on psychotropic drugs. EEG mapping represents not only a static and statistical approach by drawing the averaged maps of groups of patients but also a dynamic approach by the recording of sequential individual maps presented as an animated film. The results of this method can be correlated with other medical imaging techniques used to investigate the central nervous system.

[Methodology, limitations and value of mapping in electroencephalography]. / Méthodologie, limites et intérêt de la cartographie en électroencéphalographie.

Data processing is mandatory for EEG mapping. After having used a correct filter and ADC, spectral analysis is completed by interpolating between the spectral values obtained on each recording point to allow a sufficient number of values to be expressed in a grey or color scale on the skull projection plane. The obtention of valid results implies extreme care in data recording and processing. Transitory events (paroxysmal bursts) cannot be detected by spectral analysis. Nevertheless, EEG spectral data mapping is a very good technique to show abnormal EEG focuses in neurology, to study all sorts of neuropsychological reactivities, to follow the evolution of tracings during normal or abnormal aging, metabolic diseases or drug effects.

[EEG mapping in partial epilepsy]. / La cartographie EEG dans les épilepsies à crises partielles.

Even if mathematic treatment of EEG signals by Fast Fourier Transformation (FFT) in cases of transient epileptic discharges is still controversial, this method has been applied to 21 cases of epileptic partial seizures. Examples are shown, and compared to CT-Scan data. In 17 cases, EEG mapping identified alterations of basic activities upon a definite area. In addition, a focal peak of maximal alterations displacing itself into the limits of the whole epileptogenic area is demonstrated; it is furthermore suggested that the power spectrum keeps, especially during seizures, a peculiar ("combing") morphology, possibly specific of epileptic diseases.

Electroencephalographic Cartography. I. By means of mini- or microcomputers. Reliability and interest of this electrical non-invasive brain imagery.

We have recorded control subjects, neurological and psychiatric patients (n = 217 sequences recorded over both hemispheres). Minicomputers (HP Fourier analyzer, HP 1000) for spectral analysis provided 10 spectral parameters over 5 spectral frequency bands (delta, theta, alpha, beta 1, beta 2, raw EEG). For each recorded sequence, 90 EEG maps could be computed over both hemispheres. Topo-EEGs were stored in an EEG image data bank. An EEG mapping microcomputer system linked with a digital polygraph (Alvar Electronic, REEGA 2000) has been used simultaneously. White noises have been fed into both computers for testing spatial resolution. Ten topo-EEGs have been recorded in control subjects and patients. The microcomputer system has provided very reliable topographical results when compared to similar maps generated by the minicomputer. A common average reference has been used. First clinical applications have been studied (brain strokes, brain tumors). The method appears very reliable in comparison with CT scans.

[Contribution of the electroencephalogram to the diagnosis of vasospasm after rupture of intracranial aneurysms]. / Apport de l'électroencéphalogramme au diagnostic de vasospasme après rupture d'anévrisme intra-crânien.

This study concerns 74 patients with subarachnoid haemorrhage from ruptured supratentorial aneurysm--Serial electroencephalographic recordings (EEG) have been made with precise chronology. The first EEG (Day 1 or 2) had a prognostic value, good if it was normal, alarming if axial bursts or comatose patterns were recorded. Associated with CT scan and dosage of Fibrin degradation products in C.S.F. (F.D.P.), initial EEG gave a strong probability in predicting the occurrence of secondary ischemia. The second EEG, between Day 4 and Day 7, had a diagnostic value. When a vasospasm occurred, confirmed by further angiography, focal or unilateralized slow waves were recorded in more than 85% or these EEG. Further EEG gave the opportunity of controlling the evolution of ischemic electrical patterns.

[Herpes simplex encephalitis in neuro-surgery. Electro-encephalographic contribution to early diagnosis (author's transl)]. / Encéphalites herpétiques en neuro-chirurgie. Apport de l'EEG au diagnostic précoce.

The electroencephalographic (EEG) signs of acute necrotizing encephalitis are always focalized initially. In over 80% of the cases, the EEG shows local periodical activity with a characteristically short interval between repetitive paroxysms. This was demonstrated by the study of 17 personal observations in which herpes simplex virus was unequivocally identified as the causal agent. This EEG pattern belongs to the general group of "periodical activities". It is an early but transient finding. When observed in an acute clinical picture with fever and encephalic symptoms, it is a major diagnostic feature and should lead to immediate active therapy (neuro-surgery or chemotherapy).

[Critical follow-up study of subjects with senile plaques: neuropathological, clinical, and electroencephalographic data (author's transl)]. / Etude critique du devenir des sujets proteurs de plaques séniles. Données neuropathologiques, cliniques et électroencéphalographiques.

Frontal isocortex biopsy or operative specimens exhibited senile plaques in 25 patients aged 40 to 73 years, association with Alzheimer's "neurofibrillary degeneration" in 20 of them. These patients were followed up for up to 14 years. 3 patients died 1 to 3 months after operation. 16 patients evolved into confirmed dementia, 12 of them most probably of the Alzheimer type. 6 patients recovered fully, and their subsequent evolution appears incompatible with a diagnosis of Alzheimer's dementia (follow-up period of 3 to 14 years). Retrospective evaluation of EEG data showed a good predictive value of previously described EEG changes, as indicative of later confirmation of alzheimer's dementia.

[Herpetic meningo-encephalitis : emergency E.E.G. diagnosis and neurosurgical treatment (author's transl)]. / Apport de l'électroencéphalographie au diagnostic et au traitement neurochirurgical précoce des encéphalites herpétiques.

Reporting two cases of true herpetic encephalitis, the authors insist on the great diagnostic value of some nearly constant, but transitory, aspects of localised periodic waves in the E.E.G. An emergency cerebral (usually temporal) resection is then advised. Thus focal infection is reduced and intra-cranial hypertension is prevented. Virologic and electron microscopic studies of the cortical specimen establish with certainty the diagnosis of herpetic encephalitis.

[Association of Alzheimer's disease and Creutzfeldt-Jakob's disease (author's transl)]. / Association de maladies d'Alzheimer et de Creutzfeldt-Jakob.

Serial EEG studies and full neuropathological investigations (optic and electronic microscopy of biopsy and necropsy material) were carried out on two patients: 1. A 68-year-old man: development in two and a half months of Creutzfeldt-Jakob's disease signalled by early clinical and EEG changes and confirmed by associated spongiosis of the triad characteristic of Alzheimer's disease, which was unexpected in this case. 2. A 43-year-old man: first phase of four years of progressive deterioration, followed by an encephalopathic syndrome with myoclonus developing in twelve months. The serial EEG studies showed discontinuous periodic paroxystic activity from the start of the second phase of the disease, although the first biopsy still showed nothing but the signs of Alzheimer's disease. A fortnight later, a second biopsy revealed ultrastructural microspongiosis. Examination of necropsy material confirmed the extensive association of the characteristic images of the two processes. On the basis of these two case studies and some similar cases published in the literature, the authors discuss the possible etiological links between these two diseases and stress the importance of the EEG and cerebral biopsy for the purposes of differential diagnosis. (Acta neurol. belg., 1977, 77, 202-212).

[Curable ECHO 5 virus encephalitis. Clinical, electroencephalographic, virologic and ultrastructural study]. / Encéphalite curable à virus ECHO 5. Etude clinique, électroencéphalographique, virologique et ultrastructurale.

A 10 1/2 years old boy fell brutally ill with a fit followed by confusion, and then by deep coma, with 40 degrees C fever and morbilliform rash. Consciousnesse came back within ten days, with transient Parkinson-like tremor. Myoclonus persisted for about six months. Complete recovery was followed up for six years. A diagnosis of encephalitis was considered on early EEG evidence (stereotyped repetitive sharp wave bursts) and was confirmed by isolation of ECHO 5 virus from brain specimen, and ultrastructural observation of characteristic cytopathic effect (disappearance of organelles, proliferation of smooth membranes) and of probable viral particules in astrocytes, without any inflammatory process.